Counterbalance for crank shafts



June 20, 1933. w. 6, mm 1,914,387

COUNTERBALANCE FOR CRANK. SHAFTS Fi led Feb. 10. 1927 Wm cw s w QMWMM Patented June 20, 1933 UNITED STATES PATENT OFFICE wimna o. racer, or Lmrxm, rms

oounmnmcn ron cum: sw'rs Application filed February 10, 1927. Serial Io. 187,145.

My invention relates to an improvement in counterbalance weights to be employed in connection with crank shafts employed justable for attachment to the crank arm in position to counterbalance the weight of the pumprrods or to be shifted into a position adjacent the shaft, where it will balance the weight of the crank arm. It is desired that the weight be capable of adjustment without material difiiculty and in a minimum amount of time.

-' Referring to the drawing herewith, Fig. 1 is a somewhat diagrammatic view of a standard pumping rig showing my crank balance weight applied to the crank arm thereof. Fig. 2 is a side elevation of the crank arm with my weightv thereon, said view being somewhat enlarged. Fig. 3 is a top plan view of the arm and weight disclosed in Fig. 2.

While I have. shown the device as applied to a standard rig, it is to .be understood that its use is not necessarily confined to this particular type of equipment, as it may be employed in connection with pumping jacks or other devices whereby a load is raised and lowered in the operation thereof. Fig. 1 illustrates thepump rod 1 as being reciprocated within a well casing indicated at 2, the rod being connected with a walking beam 3 supported for rocking movement upon a Samson post 4. Said walking beam is operated through the connection by means of a pitman 5 with a crank arm 6 mounted upon the crank shaft 7, supported for rotation upon jack post 8 The band wheel 9 upon the crank shaft allows the connection therewith of power whereby the shaft may be rotated.

The crank arm in my construction is shown best in Figs. 2 and 3. Said arm is somewhat enlarged from its ordinary shape being in the form of a plate and is extended on opposite sides of the shaft to form a power arm 6 and an auxiliary arm 10, said arm 10 being materially'shorter than the arm 6' and adapted to receive and support the weight.

The outer end of the arm6' has forwardly and rearwardly extending lugs 11 thereon, said lugs being provided with o eni'n therein to receive bolts 12. The en of t e arm is formed in a lane so as to provide attachment thereto oi a weight .13.

The weight 13 may be of any desired shape or size. I have shown the outer edge thereof as being curved on the are of a circle having the shaft 7 for a center. The ends of the weight are rounded 011' and the inner side is made. plane to fit against the outer face of the arm 6', as shown in Fig. 2. The weight is provided with transverse openings 14 to allow the insertion of bolts 12 extending through the weight and through the openings in the flanges. 11 of the arm so as to-secure' the weight to the .crank arm. Nuts 15 upon said bolts permit the weight to be clamped rigidly to the outer end of the crank arm. I have shown keyways formed in the weight and in the end of the arm to receive a'key 16 therein, said key resisting any movement of the weight laterally relative to the arm in an obvious manner.

The auxiliary arm 10 is formed with laterally extending In S 11 thereon, said lugs being provided wit openings to receive the bolts 12 so that the weight may be moved to a position on the end of the auxiliary arm- 10 and be secured thereto in the same man ne'r as has been described relative to the outer end of the arm 6.

In the use of my counterbalance, the weight will be secured at the outer end of the crank arm during pumpin operations and will tend to assist the era in raising the load of the pump rods and the plunger and to resist the drop ing of the same on the downward stroke 0? the plunger. Thus,

in Figure 1, the crank arm may be under- I stood as rotating in a clockwise direction to raise the load of the pump rod 1, and it will be seen that the Weight will tend to counterbalance the weight of the rods.

On the upward movement of the weight and crank arm the pum rods will be dro ping and the Wei ht wi tend to resist t e sudden downwar movement of the rods 5 and plunger.

When it is desired to remove the connection between the crank arm and the pitman 5 so as to use the band wheel for the transmission of power to a hoisting apparatus or other similar device, the weight 13 ma be disconnected from the crank arm 6 an moved to balancin position on the arm 10, and quickly secure in place thereon. The weight 13 wil then tend to balance the 15 weight of the crank arm 6' and the rotation of the shaft 7 will be balanced so that there will be no strain 11 on the'working parts of the apparatus. Spenings 17 may be made in the weight at each end thereof 20 to provide means to attach thereto a hook or chain whereby the weight may be lifted and moved from one position to the other relative to the crank shaft without dificulty.

The advantages of the construction will be apparent to those skilled in the art without further description.

What I claim as new and desire to protect bv Letters Patent is:

1. n a device of the character described,

a crank shaft, a crank arm thereon extending radially from said shaft, an oppositely extending auxiliar arm, the ends of said arms having latera ly extending lugs thereon, and a weight adapted to fit against the said lugs and be secured thereto on either arm, for the purpose described.

2. In a device of the character described, a crank shaft, a plate secured to said shaft 43 at one end, one end of said plate formin a crank arm, laterally extending lugs at each end of said plate, a weight, and means to rigidly secure said weight to said In at. either end of said plate, said weight filing 45 bodily removable from one end of said plate 1 for attachment to the other end thereof,

for the purpose described.

3. A crank shaft, a crank arm extending radially therefrom, an auxiliary arm projecting in an op osite direction from said shaft, the ends 0 said arms being flattened, lateral lugs on said ends, a weight shaped to fit said flattened ends, and means to secure said weight to said. lugs.

In testimony whereof I hereuntoafiix my igggnzature this 5th day of February, A. D.

- WALTER C. TROUT. 

